1. Collaboration Meeting at UCI, April 7-9, 2005 ANITA Navigation and Orientation Kurt Liewer

2. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 1 High Level Requirements Position (navigation) –Position knowledge error < 10 m/axis required for calibration pulse timing –Science requirements (  E/E and source localization) are not called out but 1 km is probably adequate Orientation –azimuth knowledge error < 1.4° for localization of known sources for map reconstruction –pitch/roll knowledge error < 0.7° from requirements on energy determination (range)

3. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 2 Navigation Instrumentation Thales ADU5 GPS receiver –previously used by NSBF (CREAM) –accuracy 5 m/axis Thales G12 GPS receiver –used on ANITA-light –accuracy 5 m/axis pressure sensor –provides redundant altitude information NSBF GPS receiver More than enough accuracy and redundancy Extrapolation would be adequate for science requirements for extended periods (hours) of GPS loss of signal

4. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 3 Pointing Budget

5. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 4 Orientation Instrumentation Thales ADU5 GPS receiver in differential mode with 3 m baseline –previously used by NSBF (CREAM) –accuracy 0.06° in azimuth (heading) –accuracy 0.12° in pitch and roll –accuracy values are for 3 m baseline, no multipath and no dilution of precision On CREAM the dilution of precision ranged from 2 to 6 –average DOP ~3 CREAM (and BOOMERANG) have periods of loss of GPS but it is unknown (to me) if this is a loss of GPS signal or a loss of telemetry CREAM angle noise roughly matches expectation but has long term (hundreds of seconds) variations that seem unlikely to be real

6. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 5 Orientation Data Twenty minutes of BOOMERANG pointing data Note the change between the pitch/roll scale and the azimuth scale Std dev of pitch = 0.04° std dev of roll = 0.02°

7. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 6 Orientation Data

8. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 7 Orientation Instrumentation (cont’d) Sun sensor –covers ±22.5° in azimuth and 0° to 45° in elevation –Sun angle error < 0.5°/axis –slightly modified version of the Sun sensor flown on Anita-light –Does not unambiguously give azimuth and elevation insensitive to rotation about direction to Sun Crossbow CXL02TG3 3-axis accelerometer –two units flown with a vertical separation to allow identification angular acceleration (pendulum modes) –can not separate out effects of linear acceleration and pitch/roll –sensitivity ~ 10 -3 G

9. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 8 Crossbow CXM539 3-axis magnetometer –magnetic field thought to be too poorly known and too variable for direct measurement of angles –can be used to measure fluctuations in angles –calibration of fixed magnetic field may not be possible Combined measurements from all secondary sensors may provide adequate performance Orientation Instrumentation (cont’d)

10. April 7, 2005Collaboration Meeting at UCI, April 7-9, 2005KML - 9 Concerns Navigation –None Orientation –Primary sensor (differential GPS) may have outages –secondary sensors are on the edge of not meeting requirements –in flight calibration difficult can cross compare at some level –structure deformation due to temperature may affect interpretation